The present invention relates generally to guides which may be used in carpentry and more particularly to a guide which may be used with power hand tools, such as routers and circular saws.
During carpentry operations, it is often necessary to cut a workpiece in a line perpendicular to one edge of the workpiece. A carpenter's square is often used to facilitate this operation by aligning one leg of the square with the edge of the workpiece and scribing a line at the desired location, using the other leg of the square as a guide. A cut or groove can then be made by following the line with a cutting tool. A problem with this method is that sawdust often obscures the line or the workman has trouble holding the saw or router in a straight line as it is pushed along.
A number of guides have been devised to eliminate the need for a scribe line. A guide provides a surface against which one edge of the hand tool may be positioned as it is pushed across the workpiece. However, for the most part, these guides have been difficult to use and often prove to be unreliable because of bending or loose joints which allows the guide surface to deviate from a true perpendicular alignment.
Past guides generally have included vertically protruding elements which prevent inversion of the guide in use. As a result, only one edge can be used for alignment with the workpiece and the other edge must always be used as the guide for the power tool, pencil or the like. One such guide is disclosed in Hopla, U.S. Pat. No. 2,773,523 wherein two guide members are pivotally connected in overlapped relation so as to lie in different horizontal planes. Another problem with existing tool guides is that the length of a cut must be premeasured with a carpenter's square before the cut is made, thus requiring two operations to make a single cut. Finally, prior guides have required clamping of the guides to the workpiece to assure that the guide is properly stabilized. Clamping is a tedious and time-consuming operation.
It can be seen that a need exists for a guide tool which is reliable and easy to use. The guide tool should contain measured markings which allow the user to make a cut without premeasuring the cut with a carpenter's square. A method for stabilizing the device relative to the workpiece should also be provided, which can accommodate use with or without clamps, to prevent any movement of the guide during precise cutting.